sys/pcfs/denode.h

/*
 *  Written by Paul Popelka (paulp@uts.amdahl.com)
 *
 *  You can do anything you want with this software,
 *    just don't say you wrote it,
 *    and don't remove this notice.
 *
 *  This software is provided "as is".
 *
 *  The author supplies this software to be publicly
 *  redistributed on the understanding that the author
 *  is not responsible for the correct functioning of
 *  this software in any circumstances and is not liable
 *  for any damages caused by this software.
 *
 *  October 1992
 *
 *      $Id: denode.h,v 1.5 1993/11/25 01:37:04 wollman Exp $
 */

#ifndef _PCFS_DENODE_H_
#define _PCFS_DENODE_H_ 1

/*
 *  This is the pc filesystem specific portion of the
 *  vnode structure.
 *  To describe a file uniquely the de_dirclust, de_diroffset,
 *  and de_de.deStartCluster fields are used.  de_dirclust
 *  contains the cluster number of the directory cluster containing
 *  the entry for a file or directory.  de_diroffset is the
 *  index into the cluster for the entry describing a file
 *  or directory.  de_de.deStartCluster is the number of the
 *  first cluster of the file or directory.  Now to describe the
 *  quirks of the pc filesystem.
 *  - Clusters 0 and 1 are reserved.
 *  - The first allocatable cluster is 2.
 *  - The root directory is of fixed size and all blocks that
 *    make it up are contiguous.
 *  - Cluster 0 refers to the root directory when it is found
 *    in the startcluster field of a directory entry that points
 *    to another directory.
 *  - Cluster 0 implies a 0 length file when found in the start
 *    cluster field of a directory entry that points to a file.
 *  - You can't use the cluster number 0 to derive
 *    the address of the root directory.
 *  - Multiple directory entries can point to a directory.
 *    The entry in the parent directory points to a child
 *    directory.  Any directories in the child directory contain
 *    a ".." entry that points back to the child.  The child
 *    directory itself contains a "." entry that points to
 *    itself.
 *  - The root directory does not contain a "." or ".." entry.
 *  - Directory entries for directories are never changed once
 *    they are created (except when removed).  The size stays
 *    0, and the last modification time is never changed.  This
 *    is because so many directory entries can point to the physical
 *    clusters that make up a directory.  It would lead to an update
 *    nightmare.
 *  - The length field in a directory entry pointing to a directory
 *    contains 0 (always).  The only way to find the end of a directory
 *    is to follow the cluster chain until the "last cluster"
 *    marker is found.
 *  My extensions to make this house of cards work.  These apply
 *  only to the in memory copy of the directory entry.
 *  - A reference count for each denode will be kept since dos doesn't
 *    keep such things.
 */

/* Internal pseudo-offset for (nonexistent) directory entry for the root dir
 * in the root dir */
#define PCFSROOT_OFS    0x1fffffff

/*
 *  The fat cache structure.
 *  fc_fsrcn is the filesystem relative cluster number
 *  that corresponds to the file relative cluster number
 *  in this structure (fc_frcn).
 */
struct fatcache {
        u_short fc_frcn;        /* file relative cluster number */
        u_short fc_fsrcn;       /* filesystem relative cluster number */
};

/*
 *  The fat entry cache as it stands helps make extending
 *  files a "quick" operation by avoiding having to scan
 *  the fat to discover the last cluster of the file.
 *  The cache also helps sequential reads by remembering
 *  the last cluster read from the file.  This also prevents
 *  us from having to rescan the fat to find the next cluster
 *  to read.  This cache is probably pretty worthless if a
 *  file is opened by multiple processes.
 */
#define FC_SIZE         2       /* number of entries in the cache       */
#define FC_LASTMAP      0       /* entry the last call to pcbmap() resolved to */
#define FC_LASTFC       1       /* entry for the last cluster in the file */

#define FCE_EMPTY       0xffff  /* doesn't represent an actual cluster # */

/*
 *  Set a slot in the fat cache.
 */
#define fc_setcache(dep, slot, frcn, fsrcn) \
        (dep)->de_fc[slot].fc_frcn = frcn; \
        (dep)->de_fc[slot].fc_fsrcn = fsrcn;

/*
 *  This is the in memory variant of a dos directory
 *  entry.  It is usually contained within a vnode.
 */
struct denode {
        struct denode *de_chain[2];     /* hash chain ptrs              */
        struct vnode *de_vnode;         /* addr of vnode we are part of */
        struct vnode *de_devvp;         /* vnode of blk dev we live on  */
        u_long de_flag;                 /* flag bits                    */
        dev_t de_dev;                   /* device where direntry lives  */
        u_long de_dirclust;             /* cluster of the directory file
                                         *  containing this entry       */
        u_long de_diroffset;            /* ordinal of this entry in the
                                         *  directory                   */
        long de_refcnt;                 /* reference count              */
        struct pcfsmount *de_pmp;       /* addr of our mount struct     */
        struct lockf *de_lockf;         /* byte level lock list         */
        long de_spare0;                 /* current lock holder          */
        long de_spare1;                 /* lock wanter                  */
        struct direntry de_de;          /* the actual directory entry   */
        struct fatcache de_fc[FC_SIZE]; /* fat cache                    */
};

/*
 *  Values for the de_flag field of the denode.
 */
#define DELOCKED        0x0001          /* directory entry is locked    */
#define DEWANT          0x0002          /* someone wants this de        */
#define DERENAME        0x0004          /* de is being renamed          */
#define DEUPD           0x0008          /* file has been modified       */
#define DESHLOCK        0x0010          /* file has shared lock         */
#define DEEXLOCK        0x0020          /* file has exclusive lock      */
#define DELWAIT         0x0040          /* someone waiting on file lock */
#define DEMOD           0x0080          /* denode wants to be written back
                                         *  to disk                     */

/*
 *  Shorthand macros used to reference fields in the direntry
 *  contained in the denode structure.
 */
#define de_Name         de_de.deName
#define de_Extension    de_de.deExtension
#define de_Attributes   de_de.deAttributes
#define de_Reserved     de_de.deReserved
#define de_Time         de_de.deTime
#define de_Date         de_de.deDate
#define de_StartCluster de_de.deStartCluster
#define de_FileSize     de_de.deFileSize
#define de_forw         de_chain[0]
#define de_back         de_chain[1]

#if defined(KERNEL)

#define VTODE(vp)       ((struct denode *)(vp)->v_data)
#define DETOV(de)       ((de)->de_vnode)

#define DELOCK(de)      delock(de)
extern void delock(struct denode *);
#define DEUNLOCK(de)    deunlock(de)
extern void deunlock(struct denode *);

#define DEUPDAT(dep, t, waitfor) \
        if (dep->de_flag & DEUPD) \
                (void) deupdat(dep, t, waitfor);

#define DETIMES(dep, t) \
        if (dep->de_flag & DEUPD) { \
                (dep)->de_flag |= DEMOD; \
                unix2dostime(t, (union dosdate *)&dep->de_Date, \
                        (union dostime *)&dep->de_Time); \
                (dep)->de_flag &= ~DEUPD; \
        }

/*
 * This overlays the fid sturcture (see mount.h)
 */
struct defid {
        u_short defid_len;      /* length of structure */
        u_short defid_pad;      /* force long alignment */

        u_long  defid_dirclust; /* cluster this dir entry came from     */
        u_long  defid_dirofs;   /* index of entry within the cluster    */

/*      u_long  defid_gen;*/    /* generation number */
};

/*
 * Prototypes for PCFS vnode operations
 */
int pcfs_lookup __P((struct vnode *vp, struct nameidata *ndp, struct proc *p));
int pcfs_create __P((struct nameidata *ndp, struct vattr *vap, struct proc *p));
int pcfs_mknod __P((struct nameidata *ndp, struct vattr *vap, struct ucred *cred,
        struct proc *p));
int pcfs_open __P((struct vnode *vp, int mode, struct ucred *cred,
        struct proc *p));
int pcfs_close __P((struct vnode *vp, int fflag, struct ucred *cred,
        struct proc *p));
int pcfs_access __P((struct vnode *vp, int mode, struct ucred *cred,
        struct proc *p));
int pcfs_getattr __P((struct vnode *vp, struct vattr *vap, struct ucred *cred,
        struct proc *p));
int pcfs_setattr __P((struct vnode *vp, struct vattr *vap, struct ucred *cred,
        struct proc *p));
int pcfs_read __P((struct vnode *vp, struct uio *uio, int ioflag,
        struct ucred *cred));
int pcfs_write __P((struct vnode *vp, struct uio *uio, int ioflag,
        struct ucred *cred));
int pcfs_ioctl __P((struct vnode *vp, int command, caddr_t data, int fflag,
        struct ucred *cred, struct proc *p));
int pcfs_select __P((struct vnode *vp, int which, int fflags, struct ucred *cred,
        struct proc *p));
int pcfs_mmap __P((struct vnode *vp, int fflags, struct ucred *cred,
        struct proc *p));
int pcfs_fsync __P((struct vnode *vp, int fflags, struct ucred *cred,
        int waitfor, struct proc *p));
int pcfs_seek __P((struct vnode *vp, off_t oldoff, off_t newoff,
        struct ucred *cred));
int pcfs_remove __P((struct nameidata *ndp, struct proc *p));
int pcfs_link __P((struct vnode *vp, struct nameidata *ndp, struct proc *p));
int pcfs_rename __P((struct nameidata *fndp, struct nameidata *tdnp,
        struct proc *p));
int pcfs_mkdir __P((struct nameidata *ndp, struct vattr *vap, struct proc *p));
int pcfs_rmdir __P((struct nameidata *ndp, struct proc *p));
int pcfs_symlink __P((struct nameidata *ndp, struct vattr *vap, char *target,
        struct proc *p));
int pcfs_readdir __P((struct vnode *vp, struct uio *uio, struct ucred *cred,
        int *eofflagp));
int pcfs_readlink __P((struct vnode *vp, struct uio *uio, struct ucred *cred));
int pcfs_abortop __P((struct nameidata *ndp));
int pcfs_inactive __P((struct vnode *vp, struct proc *p));
int pcfs_reclaim __P((struct vnode *vp));
int pcfs_lock __P((struct vnode *vp));
int pcfs_unlock __P((struct vnode *vp));
int pcfs_bmap __P((struct vnode *vp, daddr_t bn, struct vnode **vpp,
        daddr_t *bnp));
int pcfs_strategy __P((struct buf *bp));
void pcfs_print __P((struct vnode *vp));
int pcfs_islocked __P((struct vnode *vp));
int pcfs_advlock __P((struct vnode *vp, caddr_t id, int op, struct flock *fl,
        int flags));

/*
 *  Internal service routine prototypes.
 */
int deget __P((struct pcfsmount *pmp, u_long dirclust, u_long diroffset,
        struct direntry *direntptr, struct denode **depp));

extern int pcbmap(struct denode *, u_long, daddr_t *, u_long *);
extern void fc_purge(struct denode *, u_int);
extern void updateotherfats(struct pcfsmount *, struct buf *, u_long);
extern int clusterfree(struct pcfsmount *, u_long, u_long *);
extern int fatentry(int, struct pcfsmount *, u_long, u_long *, u_long);
extern int clusteralloc(struct pcfsmount *, u_long *, u_long);
extern int freeclusterchain(struct pcfsmount *, u_long);
extern int fillinusemap(struct pcfsmount *);
extern int extendfile(struct denode *, struct buf **, u_int *);
extern int readep(struct pcfsmount *, u_long, u_long, struct buf **,
                  struct direntry **);
extern int readde(struct denode *, struct buf **, struct direntry **);
extern int doscheckpath(struct denode *, struct denode *);
extern int dosdirempty(struct denode *);
extern int removede(struct nameidata *);
extern int markdeleted(struct pcfsmount *, u_long, u_long);
extern int createde(struct denode *, struct nameidata *, struct denode **);
extern int pcfs_lookup(struct vnode *, struct nameidata *, struct proc *);

extern void pcfs_init(void);
extern void deput(struct denode *);
extern int deupdat(struct denode *, struct timeval *, int);
extern int detrunc(struct denode *, u_long, int);
extern void reinsert(struct denode *);
extern int pcfs_reclaim(struct vnode *);
extern int pcfs_inactive(struct vnode *, struct proc *);


#endif /* defined(KERNEL) */
#endif /* _PCFS_DENODE_H_ */